Chemistry of Essential Oils

(Tuis.) #1

MYETACE^E 353


OIL OF EUCALYPTUS CINEBEA.

This tree is the Argyle Apple of New South Wales. The oil has the
following characters:—


Specific gravity 0-911 to 0-9225
Optical rotation +24°„+ 4-25°
Eefractive index 1-4706 at 16°
Eucalyptol 59 per cent.
Yield 1 to 1-3 „
It contains eucalyptol, pinene, and esters.

OIL OF EUCALYPTUS CITBIODOBA,

This tree, the "citron-scented" eucalyptus, is found along the coast
of Queensland and as far south as Port Jackson. It has been described
as a variety of the New South Wales " spotted gum," Eucalyptus macu-
lata (which itself possesses very little odour), but Baker and Smith con-
sider it to be a separate species. This variety yields a typical scented
eucalyptus oil, having the following characters :—
Specific gravity 0*864 to 0'905
Optical rotation - 1° „ + 2°
Refractive index.1-4540 „ 1-4678
It contains a very large quantity of citronellal, one specimen, accord-
ing to Schimmel & Co., having been found to contain as much as 95 per
cent. It also contains geraniol and traces of pinene. This oil is of a
most pleasant odour, and is admirably suited for soap perfumery, pos-
sessing a far more delicate odour than ordinary citronella oil, which it
somewhat resembles in its general characteristics.

OIL OF EUCALYPTUS CNEOBIFOLIA.
This eucalypt, one of the Mallees, is chiefly found in Kangaroo
Island, South Australia. It is a comparatively small plant, seldom
reaching more than 12 to 15 ft. in height. It is known locally as the
" narrow-leaved eucalyptus". The plant was originally looked upon
as a variety of Eucalyptus oleosa, but it is now understood to be a
separate species. The oil came into commerce some few years ago
under the name of oleosa, but is quite different from the oil which was
originally known under the same name. The oil is very rich in cineol
and has the following characters :—
Specific gravity 0-899 to 0*929
Optical rotation - 3-5° „ - 12-5°
Refractive index 1-4747 at 16°
It has a secondary odour recalling that of cumin. It contains from
50 to 70 per cent, of eucalyptol and a small quantity of aromadendral
and a sesquiterpene. This oil is much valued as a medicinal oil, and
usually conforms admirably to pharmacopoeial requirements.

OIL OF EUCALYPTUS COCCIFEBA.
This oil, a Tasmanian eucalypt, has the following characters :—
Specific gravity 0-881
Optical rotation_- 35*8°
Saponification value ........ 4-9
Eefractive index 1-4831 at 24°
VOL. I. 23
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